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Chemical Reactions and Equations
Class 1 0 Important Questions with
Answers Science Chapter 1
July 5, 2022 by topper 7777
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We have given these Important Questions for Class 10 Science Chapter 1 Chemical
Reactions and Equations to solve different types of questions in the exam. Previous
Year Questions & Important Questions of Chemical Reactions and Equations Class 10
Science Chapter 1 will help the students to score good marks in the board examination.
Important Questions of Chemical Reactions
and Equations Class 1 0 Science Chapter 1
Question 1.
Identify ‘x’, ‘y’ and ‘z’ in the following reaction :
(a) x = gas; y = reaction condition; z = gas
(b) x = solid; y = liquid; z = gas
(c) x = number of moles of KClO3; y = reaction condition; z = number of molecules of
oxygen
(d) x = physical state of KClO3 and KCl;
y = reaction condition, z = physical state of O2. (2020)
Answer:
Chemistry online courses
, Physics textbooks
Question 2.
Assertion (A) : Following is a balanced chemical equation for the action of steam on
iron : 3Fe + 4H2O → Fe3O4 + 4H2
Reason (R): The law of conservation of mass holds good for a chemical equation.
(a) Both (A) and (R) are true and reason (R) is the correct explanation of the assertion
(A)
(b) Both (A) and (R) are true, but reason (R) is not the correct explanation of the
assertion (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true. (2020)
Answer:
A balanced chemical equation must obey the law of conservation of mass.
Question 3.
(a) State the law that is followed by balancing a chemical equation.
(b) Balance the following chemical equation: Na + H3O → NaOH + H2 (Board Term I,
2013)
Answer:
(a) Law of conservation of mass is followed for balancing a chemical equation which
states that mass can neither be created nor destroyed in a chemical reaction. That is,
the total mass of the elements present in the products of a chemical reaction has to be
equal to the total mass of the elements present in the reactants in a balanced equation.
(b) 2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)
Question 4.
Explain the significance of photosynthesis.
Write the balanced chemical equation involved in the process. (Board Term I, 2017)
Answer:
Photosynthesis means synthesis with the help of light. It is the process that gives life to
all living beings.
Photosynthesis is a process by which plants utilize carbon dioxide and water in the
presence of sunlight to produce glucose and oxygen.
Question 5.
Write balanced chemical equations for the following chemical reactions:
(a) Hydrogen + Chlorine → Hydrogen chloride
(b) Lead + Copper chloride → Lead chloride + Copper
(c) Zinc oxide + Carbon → Zinc + Carbon monoxide (Board Term I, 2014)
Answer:
Chemical Reactions and Equations
Class 1 0 Important Questions with
Answers Science Chapter 1
July 5, 2022 by topper 7777
Chemistry online courses
Powered by
We have given these Important Questions for Class 10 Science Chapter 1 Chemical
Reactions and Equations to solve different types of questions in the exam. Previous
Year Questions & Important Questions of Chemical Reactions and Equations Class 10
Science Chapter 1 will help the students to score good marks in the board examination.
Important Questions of Chemical Reactions
and Equations Class 1 0 Science Chapter 1
Question 1.
Identify ‘x’, ‘y’ and ‘z’ in the following reaction :
(a) x = gas; y = reaction condition; z = gas
(b) x = solid; y = liquid; z = gas
(c) x = number of moles of KClO3; y = reaction condition; z = number of molecules of
oxygen
(d) x = physical state of KClO3 and KCl;
y = reaction condition, z = physical state of O2. (2020)
Answer:
Chemistry online courses
, Physics textbooks
Question 2.
Assertion (A) : Following is a balanced chemical equation for the action of steam on
iron : 3Fe + 4H2O → Fe3O4 + 4H2
Reason (R): The law of conservation of mass holds good for a chemical equation.
(a) Both (A) and (R) are true and reason (R) is the correct explanation of the assertion
(A)
(b) Both (A) and (R) are true, but reason (R) is not the correct explanation of the
assertion (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true. (2020)
Answer:
A balanced chemical equation must obey the law of conservation of mass.
Question 3.
(a) State the law that is followed by balancing a chemical equation.
(b) Balance the following chemical equation: Na + H3O → NaOH + H2 (Board Term I,
2013)
Answer:
(a) Law of conservation of mass is followed for balancing a chemical equation which
states that mass can neither be created nor destroyed in a chemical reaction. That is,
the total mass of the elements present in the products of a chemical reaction has to be
equal to the total mass of the elements present in the reactants in a balanced equation.
(b) 2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)
Question 4.
Explain the significance of photosynthesis.
Write the balanced chemical equation involved in the process. (Board Term I, 2017)
Answer:
Photosynthesis means synthesis with the help of light. It is the process that gives life to
all living beings.
Photosynthesis is a process by which plants utilize carbon dioxide and water in the
presence of sunlight to produce glucose and oxygen.
Question 5.
Write balanced chemical equations for the following chemical reactions:
(a) Hydrogen + Chlorine → Hydrogen chloride
(b) Lead + Copper chloride → Lead chloride + Copper
(c) Zinc oxide + Carbon → Zinc + Carbon monoxide (Board Term I, 2014)
Answer:
